## Copyright (C) 2007   Sylvain Pelissier   <sylvain.pelissier@gmail.com>
##
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program; If not, see <http://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn {Function File} {[@var{psi,x}] =} mexihat(@var{lb,ub,n})
##	Compute the Mexican hat wavelet.
## @end deftypefn

function [psi,x] = mexihat(lb,ub,n)
	if (nargin < 3); usage('[psi,x] = mexihat(lb,ub,n)'); end
	
	if (n <= 0)
		error("n must be strictly positive");
	endif
	x = linspace(lb,ub,n);
	psi = (1-x.^2).*(2/(sqrt(3)*pi^0.25)) .* exp(-x.^2/2)  ;
endfunction